CVE-2000-0549

MEDIUM

Kerberos 4 KDC program does not properly check for null termination of AUTH_MSG_KDC_REQUEST requests, which allows remote attackers to cause a denial of service via a malformed request.

Affects 4 products across 2 vendors.

CVSS 2.05.0
EPSS2.3%
Percentile83th
PatchUnknown
CVSS Vector — Plain English Remotely exploitable over the network, low complexity, no confidentiality impact, no integrity impact.
◆ AI Analysis — automated analysis, not human-reviewed

This vulnerability was disclosed in 2000. A medium severity vulnerability affects Cygnus systems (CVE-2000-0549). No public exploit code is currently available. Isolate affected systems if patching is not feasible.

BSID: BS-2000-GLOBAL-308842-M • Model: rule-based-v1 • Confidence: MEDIUM

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Frequently Asked Questions
What is CVE-2000-0549?
This vulnerability was disclosed in 2000. A medium severity vulnerability affects Cygnus systems (CVE-2000-0549). No public exploit code is currently available. Isolate affected systems if patching is not feasible.
What is the CVSS score for CVE-2000-0549?
CVE-2000-0549 has CVSS 5.0 (Medium). Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P. EPSS: 2.3%.
Is CVE-2000-0549 actively exploited?
No confirmed active exploitation of CVE-2000-0549 as of 2026-09-25.
How do I remediate CVE-2000-0549?
Priority: MONITOR. PSIRT: [email protected]
What systems are affected by CVE-2000-0549?
CVE-2000-0549 affects Cygnus Cygnus Network Security, Kerbnet; Mit Kerberos, Kerberos 5.
Vulnerability Details
CVE IDCVE-2000-0549
BSIDBS-2000-GLOBAL-308842-M BreachSpider Global ID
CVSS VectorAV:N/AC:L/Au:N/C:N/I:N/A:P
Published2000-06-09
Last Modified2026-06-16
ICS Relevance0%
SourceNVD
Official Description

Kerberos 4 KDC program does not properly check for null termination of AUTH_MSG_KDC_REQUEST requests, which allows remote attackers to cause a denial of service via a malformed request.

Source: NIST NVD / MITRE CVE Database

Attack Vector Analysis — CITED Relevance

Vulnerability details: Kerberos 4 KDC program does not properly check for null termination of AUTH_MSG_KDC_REQUEST requests, which allows remote attackers to cause a denial of service via a malformed request. CVSS vector: AV:N/AC:L/Au:N/C:N/I:N/A:P.

Exploitation Likelihood: MINIMAL

Affected Products
VendorProductAffected Versions
Cygnus Cygnus Network Security 4.0
Cygnus Kerbnet 5.0
Mit Kerberos 4.0
Mit Kerberos 5 1.0 1.1 1.1.1 4.0
Remediation

No official vendor advisory link on record. See the CVE record →

Vendor PSIRT: [email protected]
Threat Intelligence
● Threat Intelligence Validated: October 2026 | Threat Age: 9625 Days
CISA known-exploitedNot in KEV catalog
Public ExploitNot confirmed
PoC CodeNot confirmed
AI Enrichment Record — provenance & audit hash
Modelrule-based-v1
ConfidenceMEDIUM
Enriched At2026-05-24
SHA-512 Audit Hash069e07931754a6fb481b10d986e9f6bfba3a16a671e7b297195d9f96e0539a2e9865ae4bc39ff44035214072ce95b6f250a4e1f317d026246d8dff73bc05b7ba
Related CVEs affecting Cygnus
CVE-2000-0389 10.0 Buffer overflow in krb_rd_req function in Kerberos 4 and 5 allows remote atta... CVE-2000-0390 10.0 Buffer overflow in krb425_conv_principal function in Kerberos 5 allows remote... CVE-2000-0391 10.0 Buffer overflow in krshd in Kerberos 5 allows remote attackers to gain root p... CVE-2000-0392 7.2 Buffer overflow in ksu in Kerberos 5 allows local users to gain root privileges. CVE-2000-0550 5.0 Kerberos 4 KDC program improperly frees memory twice (aka "double-free"), whi...
View all Cygnus CVEs →

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